The present invention relates to optical devices for use by color blind viewers and more particularly, to eyeglasses which improve the ability of a color blind viewer to discriminate between different colored objects.
A large proportion of the population suffers from some form of color blindness which reduces eye discrimination of different colored objects. For example, a common form of color blindness is known as red/green color blindness wherein the eyes of a viewer cannot distinguish between the colors red and green. Thus, if a red/green color blind viewer were to look at an apple tree, any red apples would not stand out from the otherwise green leaves of the tree and the primary way that the apples could be distinguished would be by viewer recognition of the apple outline. Obviously, this condition causes increased viewer problems in object discrimination and even more problems when it is necessary to distinguish between red and green under circumstances where other characteristics (e.g. shape, outline, etc.) are not distinguishable.
In the prior art, optical filtering devices have been used to aid in the color discrimination between different colored objects. In U.S. Pat. No. 3,877,797, for example, optical filters are disclosed which alter the illuminating radiations of a light source or alter the object reflected radiations received by a viewer's eye in order to enhance color discrimination between objects of different colors. This particular patent achieves such results by forming an optical filter (which can be the lens structure of eyeglasses or spectacles) to remove two selected bands of radiation having variable bandwidth.
While the above technique and others may provide certain advantages in color discrimination, there is still a need for devices which aid color discrimination for color blind viewers. Accordingly, the present invention has been developed to provide a simple and inexpensive device for aiding object discrimination and more particularly, to provide eyeglasses which aid in color discrimination, but which appear to be conventionally constructed.